Usually, for prevention of corrosion, large-sized steel structures such as ships, land structures, and bridges are subjected to anticorrosive coating using an anticorrosive coating composition. In the anticorrosive coating, an anticorrosive coating composition is applied on a surface of a steel plate or the like to form an anticorrosive coating film having a thickness of several hundred to several thousand micrometers. This allows the surface of the steel plate or the like to be covered with the anticorrosive coating film to prevent the steel plate or the like from contacting with oxygen, salt, vapor, and the like, thereby preventing the corrosion of the steel plate or the like.
Meanwhile, on welding lines or edges, where film thickness is difficult to ensure, stripe coating is performed by using a brush or a roller. Coating using a brush or a roller, as compared with spray coating, lets bubbles remain on the surfaces of the coating film, consequently impairing the appearance of the coating film. Thus, a defoaming agent is generally added to a coating material.
Known examples of the defoaming agent include silicone-based defoaming agents and acrylic/vinyl ether-based defoaming agents.
As the coating composition, Applicant of the present invention has disclosed an anticorrosive coating composition containing a non-tar-based epoxy resin, a curing agent, an epoxy group-containing alkoxysilane compound, a specific flaky pigment and an extender pigment (Patent Literature 1).
Patent Literature 2 discloses an epoxy resin coating composition containing a silicone-based defoaming agent; Patent Literature 3 discloses an epoxy resin coating composition containing an acrylic/vinyl ether-based defoaming agent; and Patent Literature 4 discloses an epoxy coating composition containing polyolefin wax.